Harrison
Content
HARRISON -Health Care–Associated Infections:
Given the prominence of cross-infection, hand hygiene is the single most
important preventive measure in hospitals
Health care workers' rates of adherence to hand-hygiene recommendations are
abysmally low (<50%).
Use of alcohol hand rubs between patient contacts is now recommended for all
health care workers except when hands are visibly soiled or after care of a patient
who is part of a health-care facility outbreak of infection with Clostridium difficile,
whose spores resist killing by alcohol and require mechanical removal. In
these cases, washing with soap and running water is recommended.
at least 25–50% of nosocomial infections are due to the combined effect of
the patient's own flora and invasive devices
Examples of "Bundled Interventions" to Prevent Common Health Care–Associated Infections
and Other Adverse Events
Prevention of Central Venous Catheter Infections
Educate personnel about catheter insertion and care.
Use chlorhexidine to prepare the insertion site.
Use maximal barrier precautions during catheter insertion.
Consolidate insertion supplies (e.g., in an insertion kit or cart).
Use a checklist to enhance adherence to the bundle.
Empower nurses to halt insertion if asepsis is breached.
Cleanse patients daily with chlorhexidine.
Ask daily: Is the catheter needed? Remove catheter if not needed or used.
Prevention of Ventilator-Associated Pneumonia and Complications
Elevate head of bed to 30–45 degrees.
Decontaminate oropharynx regularly with chlorhexidine.
Give "sedation vacation" and assess readiness to extubate daily.
Use peptic ulcer disease prophylaxis.
Use deep-vein thrombosis prophylaxis (unless contraindicated).
Prevention of Surgical-Site Infections
Choose a surgeon wisely.
Administer prophylactic antibiotics within 1 h before surgery; discontinue within 24 h.
Limit any hair removal to the time of surgery; use clippers or do not remove hair at all.
Prepare surgical site with chlorhexidine-alcohol.
Maintain normal perioperative glucose levels (cardiac surgery patients).a
Maintain perioperative normothermia (colorectal surgery patients).a
Prevention of Urinary Tract Infections
Place bladder catheters only when absolutely needed (e.g., to relieve obstruction), not solely for
the provider's convenience.
Use aseptic technique for catheter insertion and urinary tract instrumentation.
Minimize manipulation or opening of drainage systems.
Ask daily: Is the bladder catheter needed? Remove catheter if not needed.
Prevention of Pathogen Cross-Transmission
Cleanse hands with alcohol hand rub before and after all contacts with patients or their
environments.
Urinary tract infections (UTIs) account for 34% of nosocomial infections; up to 3% of
bacteriuric patients develop bacteremia
UTIs generally are caused by pathogens that spread up the periurethral space from
the patient's perineum or gastrointestinal tract—the most common pathogenesis in
women
The most common pathogens are Escherichia coli, nosocomial gram-negative bacilli,
enterococci, and Candida
although Candida is now the most common pathogen in nosocomial UTIs in patients
on intensive care units (ICUs), treatment of candiduria is often unsuccessful and is
recommended only when there is upper-pole or bladder-wall invasion, obstruction,
neutropenia, or immunosuppression.
early-onset nosocomial pneumonia, which manifests within the first 4 days of
hospitalization, is most often caused by community-acquired pathogens such as
Streptococcus pneumoniae and Haemophilus species,
Late-onset pneumonias most commonly are due to S. aureus, P. aeruginosa,
Enterobacter species, Klebsiella pneumoniae, or Acinetobacter
most common risks for postoperative wound infection are related to the surgeon's
technical skill, the patient's underlying diseases (e.g., diabetes mellitus, obesity) or
advanced age, and inappropriate timing of antibiotic prophylaxis. Additional risk
factors include the presence of drains, prolonged preoperative hospital stays,
shaving of the operative site by razor the day before surgery, a long duration of
surgery, and infection at remote sites (e.g., untreated UTI).
The most common pathogens in postoperative wound infections are S. aureus,
coagulase-negative staphylococci, and enteric and anaerobic bacteria.
In rapidly progressing postoperative infections, which manifest within 24–48 h of a
surgical procedure, the level of suspicion regarding group A streptococcal or
clostridial infection should be high.
Intravascular device–related bacteremias cause 14% of nosocomial infections;
central vascular catheters (CVCs) account for most of these bloodstream infections.
Intrinsic (during the manufacturing process) or extrinsic (on-site in a health care
facility) contamination of infusate, although rare, is the most common cause of
epidemic device-related bloodstream infection; extrinsic contamination may cause
up to half of endemic bacteremias related to arterial infusions used for
hemodynamic monitoring.
The most common pathogens isolated from vascular device–associated
bacteremias include coagulase-negative staphylococci, S. aureus (with 50% of
isolates in the United States resistant to methicillin), enterococci, nosocomial gramnegative bacilli, and Candida.
Many pathogens, especially staphylococci, produce extracellular polysaccharide
biofilms that facilitate attachment to catheters and provide sanctuary from
antimicrobial agents.
"Quorum-sensing" proteins help bacterial cells communicate during biofilm
development.
Wearing gloves does not replace the need for hand hygiene because hands
sometimes (in up to 20% of interactions) become contaminated during wearing or
removal of gloves.
With occurrence of localized outbreaks of avian (H5N1) influenza in Asia over the past few
years, concerns about potential pandemic influenza led to recommendations for universal
"respiratory hygiene and cough etiquette" (basically, "cover your cough"), as described and
promoted in the CDC's 2007 Guideline for Isolation Precautions, and for "source containment"
(e.g., use of face masks and spatial separation) for outpatients with potentially infectious
respiratory illnesses; to re-examinations of the value in the 1918–1919 influenza pandemic of
nonpharmacologic interventions, such as "social distancing" (e.g., closing schools and
community venues); and to debate about the level of respiratory protection required for health
care workers (i.e., whether to use the higher-efficiency N95 respirators recommended for
airborne isolation rather than the surgical masks used for droplet precautions).
A new, more virulent strain of C. difficile—BI/NAP1/027—has emerged in North America,
and overall rates of C. difficile–associated diarrhea (Chap. 129) have increased, especially among
older patients, in U.S. hospitals during the past few years.
Important measures for the control of tuberculosis (Chap. 165) include prompt recognition,
isolation, and treatment of cases; recognition of atypical presentations (e.g., lower-lobe infiltrates
without cavitation); use of negative-pressure, 100% exhaust, private isolation rooms with
closed doors and at least 6–12 air changes per hour; use of N95 respirators by caregivers
entering isolation rooms; possible use of high-efficiency particulate air filter units and/or
ultraviolet lights for disinfecting air when other engineering controls are not feasible or reliable
The potential for an outbreak of group A streptococcal infection should be
considered when even a single nosocomial case occurs. Most outbreaks involve
surgical wounds and are due to the presence of an asymptomatic carrier in the
operating room. Investigation can be confounded by carriage at extrapharyngeal
sites such as the rectum and vagina.
Routine surveillance among neutropenic patients for infections with filamentous
fungi, such as Aspergillus and Fusarium, helps hospitals to determine whether they
are facing unduly extensive environmental risks
Nosocomial Legionella pneumonia is most often due to contamination of potable
water and predominantly affects immunosuppressed patients, particularly those
receiving glucocorticoid medications.
Antibiotic-Resistant Bacteria
Molecular typing (e.g., pulsed-field gel electrophoresis) can help differentiate an outbreak due to
a single strain (which necessitates an emphasis on hand hygiene and an evaluation of potential
common-source exposures) from one that is polyclonal (which requires an emphasis on antibiotic
prudence and device bundles
Second, in the ongoing global reemergence of nosocomial multidrug-resistant gram-negative
bacilli, new problems include plasmid-mediated resistance to fluoroquinolones, metallo-betalactamase-mediated resistance to carbapenems, strains of K. pneumoniae that contain
carbapenemases (KPCs), and panresistant strains of Acinetobacter. Many multidrug-resistant
gram-negative bacilli are susceptible only to colistin, a drug that is consequently being
"rediscovered."
there has been increasing community-based spread of E. coli strains harboring an enzyme,
CTX-M, that renders them broadly resistant to beta-lactam antibiotics; given the
community focus of spread, these strains may be seen as a gramnegative version of CAMRSA.
Finally, clinical infections with MRSA strains exhibiting high-level vancomycin resistance due to
VRE-derived plasmids have been reported in a few patients—almost all in the United States and
most in Michigan—in the setting of prolonged or repeated treatment with vancomycin and/or
VRE colonization. Much more common is vancomycin "MIC creep": increasing prevalence of
MRSA strains that exhibit upper-limit susceptibility to vancomycin.
Given the prominence of cross-infection, hand hygiene is the single most
important preventive measure in hospitals
Health care workers' rates of adherence to hand-hygiene recommendations are
abysmally low (<50%).
Use of alcohol hand rubs between patient contacts is now recommended for all
health care workers except when hands are visibly soiled or after care of a patient
who is part of a health-care facility outbreak of infection with Clostridium difficile,
whose spores resist killing by alcohol and require mechanical removal. In
these cases, washing with soap and running water is recommended.
at least 25–50% of nosocomial infections are due to the combined effect of
the patient's own flora and invasive devices
Examples of "Bundled Interventions" to Prevent Common Health Care–Associated Infections
and Other Adverse Events
Prevention of Central Venous Catheter Infections
Educate personnel about catheter insertion and care.
Use chlorhexidine to prepare the insertion site.
Use maximal barrier precautions during catheter insertion.
Consolidate insertion supplies (e.g., in an insertion kit or cart).
Use a checklist to enhance adherence to the bundle.
Empower nurses to halt insertion if asepsis is breached.
Cleanse patients daily with chlorhexidine.
Ask daily: Is the catheter needed? Remove catheter if not needed or used.
Prevention of Ventilator-Associated Pneumonia and Complications
Elevate head of bed to 30–45 degrees.
Decontaminate oropharynx regularly with chlorhexidine.
Give "sedation vacation" and assess readiness to extubate daily.
Use peptic ulcer disease prophylaxis.
Use deep-vein thrombosis prophylaxis (unless contraindicated).
Prevention of Surgical-Site Infections
Choose a surgeon wisely.
Administer prophylactic antibiotics within 1 h before surgery; discontinue within 24 h.
Limit any hair removal to the time of surgery; use clippers or do not remove hair at all.
Prepare surgical site with chlorhexidine-alcohol.
Maintain normal perioperative glucose levels (cardiac surgery patients).a
Maintain perioperative normothermia (colorectal surgery patients).a
Prevention of Urinary Tract Infections
Place bladder catheters only when absolutely needed (e.g., to relieve obstruction), not solely for
the provider's convenience.
Use aseptic technique for catheter insertion and urinary tract instrumentation.
Minimize manipulation or opening of drainage systems.
Ask daily: Is the bladder catheter needed? Remove catheter if not needed.
Prevention of Pathogen Cross-Transmission
Cleanse hands with alcohol hand rub before and after all contacts with patients or their
environments.
Urinary tract infections (UTIs) account for 34% of nosocomial infections; up to 3% of
bacteriuric patients develop bacteremia
UTIs generally are caused by pathogens that spread up the periurethral space from
the patient's perineum or gastrointestinal tract—the most common pathogenesis in
women
The most common pathogens are Escherichia coli, nosocomial gram-negative bacilli,
enterococci, and Candida
although Candida is now the most common pathogen in nosocomial UTIs in patients
on intensive care units (ICUs), treatment of candiduria is often unsuccessful and is
recommended only when there is upper-pole or bladder-wall invasion, obstruction,
neutropenia, or immunosuppression.
early-onset nosocomial pneumonia, which manifests within the first 4 days of
hospitalization, is most often caused by community-acquired pathogens such as
Streptococcus pneumoniae and Haemophilus species,
Late-onset pneumonias most commonly are due to S. aureus, P. aeruginosa,
Enterobacter species, Klebsiella pneumoniae, or Acinetobacter
most common risks for postoperative wound infection are related to the surgeon's
technical skill, the patient's underlying diseases (e.g., diabetes mellitus, obesity) or
advanced age, and inappropriate timing of antibiotic prophylaxis. Additional risk
factors include the presence of drains, prolonged preoperative hospital stays,
shaving of the operative site by razor the day before surgery, a long duration of
surgery, and infection at remote sites (e.g., untreated UTI).
The most common pathogens in postoperative wound infections are S. aureus,
coagulase-negative staphylococci, and enteric and anaerobic bacteria.
In rapidly progressing postoperative infections, which manifest within 24–48 h of a
surgical procedure, the level of suspicion regarding group A streptococcal or
clostridial infection should be high.
Intravascular device–related bacteremias cause 14% of nosocomial infections;
central vascular catheters (CVCs) account for most of these bloodstream infections.
Intrinsic (during the manufacturing process) or extrinsic (on-site in a health care
facility) contamination of infusate, although rare, is the most common cause of
epidemic device-related bloodstream infection; extrinsic contamination may cause
up to half of endemic bacteremias related to arterial infusions used for
hemodynamic monitoring.
The most common pathogens isolated from vascular device–associated
bacteremias include coagulase-negative staphylococci, S. aureus (with 50% of
isolates in the United States resistant to methicillin), enterococci, nosocomial gramnegative bacilli, and Candida.
Many pathogens, especially staphylococci, produce extracellular polysaccharide
biofilms that facilitate attachment to catheters and provide sanctuary from
antimicrobial agents.
"Quorum-sensing" proteins help bacterial cells communicate during biofilm
development.
Wearing gloves does not replace the need for hand hygiene because hands
sometimes (in up to 20% of interactions) become contaminated during wearing or
removal of gloves.
With occurrence of localized outbreaks of avian (H5N1) influenza in Asia over the past few
years, concerns about potential pandemic influenza led to recommendations for universal
"respiratory hygiene and cough etiquette" (basically, "cover your cough"), as described and
promoted in the CDC's 2007 Guideline for Isolation Precautions, and for "source containment"
(e.g., use of face masks and spatial separation) for outpatients with potentially infectious
respiratory illnesses; to re-examinations of the value in the 1918–1919 influenza pandemic of
nonpharmacologic interventions, such as "social distancing" (e.g., closing schools and
community venues); and to debate about the level of respiratory protection required for health
care workers (i.e., whether to use the higher-efficiency N95 respirators recommended for
airborne isolation rather than the surgical masks used for droplet precautions).
A new, more virulent strain of C. difficile—BI/NAP1/027—has emerged in North America,
and overall rates of C. difficile–associated diarrhea (Chap. 129) have increased, especially among
older patients, in U.S. hospitals during the past few years.
Important measures for the control of tuberculosis (Chap. 165) include prompt recognition,
isolation, and treatment of cases; recognition of atypical presentations (e.g., lower-lobe infiltrates
without cavitation); use of negative-pressure, 100% exhaust, private isolation rooms with
closed doors and at least 6–12 air changes per hour; use of N95 respirators by caregivers
entering isolation rooms; possible use of high-efficiency particulate air filter units and/or
ultraviolet lights for disinfecting air when other engineering controls are not feasible or reliable
The potential for an outbreak of group A streptococcal infection should be
considered when even a single nosocomial case occurs. Most outbreaks involve
surgical wounds and are due to the presence of an asymptomatic carrier in the
operating room. Investigation can be confounded by carriage at extrapharyngeal
sites such as the rectum and vagina.
Routine surveillance among neutropenic patients for infections with filamentous
fungi, such as Aspergillus and Fusarium, helps hospitals to determine whether they
are facing unduly extensive environmental risks
Nosocomial Legionella pneumonia is most often due to contamination of potable
water and predominantly affects immunosuppressed patients, particularly those
receiving glucocorticoid medications.
Antibiotic-Resistant Bacteria
Molecular typing (e.g., pulsed-field gel electrophoresis) can help differentiate an outbreak due to
a single strain (which necessitates an emphasis on hand hygiene and an evaluation of potential
common-source exposures) from one that is polyclonal (which requires an emphasis on antibiotic
prudence and device bundles
Second, in the ongoing global reemergence of nosocomial multidrug-resistant gram-negative
bacilli, new problems include plasmid-mediated resistance to fluoroquinolones, metallo-betalactamase-mediated resistance to carbapenems, strains of K. pneumoniae that contain
carbapenemases (KPCs), and panresistant strains of Acinetobacter. Many multidrug-resistant
gram-negative bacilli are susceptible only to colistin, a drug that is consequently being
"rediscovered."
there has been increasing community-based spread of E. coli strains harboring an enzyme,
CTX-M, that renders them broadly resistant to beta-lactam antibiotics; given the
community focus of spread, these strains may be seen as a gramnegative version of CAMRSA.
Finally, clinical infections with MRSA strains exhibiting high-level vancomycin resistance due to
VRE-derived plasmids have been reported in a few patients—almost all in the United States and
most in Michigan—in the setting of prolonged or repeated treatment with vancomycin and/or
VRE colonization. Much more common is vancomycin "MIC creep": increasing prevalence of
MRSA strains that exhibit upper-limit susceptibility to vancomycin.
